Does Undine fall in love with Elmer Moffatt when they live in Apex City?

Undine and Elmer had a sufficiently passionate time together back on their hometown of Apex. It was deep enough for them to elope and get married in secret, only to have the union annulled by Undine's father. This is a fact that most people miss from the novel The Custom of the Country but you can read more about it in the book A Historical Guide to Edith Wharton, specifically on page 97.
Therefore, the answer is that Undine and Elmer must have definitely fallen in love as youngsters living in Apex City, where the rules of courtship and romance are totally different than in old money New York. This is the reason why, when Undine discovers that Elmer is now meandering in the same social circles as she is, she becomes terrified thinking about what could happen if anyone in her current "set" discovers that she was married before.
She felt that in the Marvell set Elmer Moffatt would have been stamped as "not a gentleman." Nevertheless something in his look seemed to promise the capacity to develop into any character he might care to assume; though it did not seem probable that, for the present, that of a gentleman would be among them.
She goes as far as discussing this with Elmer himself, when she literally begs him not to ruin her current engagement to Marvell by disclosing any information about them having been together.
But there is more that Undine is hiding. Right before she eloped with Elmer back in Apex, she was also engaged for two years to yet another man. So, Undine has quite a lot to brush under the rug now that she is currently engaged to Ralph Marvell, who is related to one of the old-money families that Undine is so fixated on.
http://archive.org/stream/thecustomoftheco11052gut/11052-8.txt